Looking to start your own ghost-busting business? You're going to want a Mr. Ghost iPhone EMF Detector ($20). This nifty gadget plugs into the headphone port of your iPhone or iPod touch, and lets you check for potentially spooky electromagnetic radiation via a companion app. When you're not looking for stray souls, you can use it to check the levels of electromagnetic radiation sources in your home or office — things like your TV, clock, gaming system, or small child who just ate one of his "smart" toys.